Derivative Instruments- Fair Value of Derivative Contracts Falling under Early Termination Provisions in Net Liability Position (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014
A-
Credit Derivatives [Line Items]
Potential close-out exposures (fair value)	$ 28	[1]
BBB
Credit Derivatives [Line Items]
Potential close-out exposures (fair value)	670	[1]
BB plus
Credit Derivatives [Line Items]
Potential close-out exposures (fair value)	1,862	[1]
A3
Credit Derivatives [Line Items]
Potential close-out exposures (fair value)	28	[1]
Baa2
Credit Derivatives [Line Items]
Potential close-out exposures (fair value)	670	[1]
Ba1
Credit Derivatives [Line Items]
Potential close-out exposures (fair value)	$ 1,862	[1]

[1] The amounts represent potential total close-out values if The Bank of New York Mellon’s rating were to immediately drop to the indicated levels.